Automobile headlight control



Ost. 29, 1940.

H. A. BERG, JR

AUTOMOBILE HEADLIGHT CONTROL Filed Feb. 26, '.1957

2 Sheets-Sheet l @M .www ATTO R N EYS Odi. 29, 1940. H. A. BERG, JR 2,219,976

AUTOMOBILE HEADLIGHT CONTROL Filed Feb. 26. 1937 2 Sheets-Sheet 2 INVENTOR Patented Oct. 29, 1940 UNITED STATES 2,219,976 AUTOMOBILE nEAnuGnT ooNmoL Henry A. Berg, Jr., Pittsburgh, Pa., assignor of one-third to Luther L. Guthrie, Butler, Pa., and

one-third to Chester A, Roeder, St.

Louis, Mo.

Application February Z6, 1937, Serial No. 127,867

12 Claims.

My invention relates to automobiles, and consists in means for automatically deiiecting or dimming the light-beams projected by the headlights of such vehicles.

Some years ago it was proposed to employ a selium cell. a so-called photo-electric cell, for controlling the automatic dimming of headlights. More specifically, it was proposed to install a photo-electric cell in such position on a car that the light beams of cars approaching in opposite direction would impinge and play upon the cell. Such change in illumination of the cell was in known way adapted to produce or modify an electric current, and in known way such electric current was adapted to operate an electric relay. And such operation of the relay was employed to eil'ect the automatic deiiectingfor dimming of the headlight beams of the car.

So far as I am aware, all of the various apparatus proposed hitherto proved impractical. They were too delicate, either electrically or structurally; in many cases they embodied devices which were too costly to manufacture; and in most cases, if not all, the proposed apparatus were incapable of developing sufficiently positive operation from energy supplied by the storage battery of an automobile. There probably are other reasons for the failures, but whatever they are the fact remains that no one has developed apparatus which has lled the bill.

More particularly, my invention consists in apparatus embodying a novel organization of electrical devices, by virtue of which the automatic dimming, or deilecting, of the headlight beams of an automobile becomes practical, both economically and technically.

In the accompanying drawings Fig. I is a diagrammatic view of an electrical organization` embodying the invention; and Fig. II is a diagrammatic view of the organization, illustrating certain modications.

Referring to Fig. I, the reference numerals I, I indicate the electric lamps of the two headlights (not shown) of an automobile, and 2 the usual electric storage battery. The lamps are shown to be of the conventional dual filament type; that is, each lamp includes two filaments 3 and 4. Filament 3, when energized, generates light of relatively high intensity, and filament 4 generates light of lower intensity. When the illaments 3 are energized, the headlights of the car project beams of high intensity and relatively great reach on the roadway in advance of the car, and. when the filaments 4 are energized, the

beams are of lower intensity, and are projected body, as indicated at or deflected downward upon the roadway in front of the car. Normally, when driving at night, the filaments 3 are energized, and the intensity and glare of the light beams tend to blind the drivers of cars approaching in opposite direction, wherefore courtesy, if not legal regulation, demands that the light beams be temporarily deflected or dimmed. As intimated above, the deflecting or dimming of the beams may be accomplished by de-energizing laments 3 ments 4. 'Ihe invention consists in automatic means to this end.

The normal energizing circuit of the laments 3 runs from the positive side of battery 2, through and energizing iila- 10 switch 5 (usually located on the dashboard of the 15 car), and wire 6 to the positive terminals of such filaments, and the negative terminals of the filaments are grounded (in common with the negative terminals of filaments 4) in the metal body of the car, as indicated at 1, while the negative terminal of the battery 2 is grounded to the car 8. In accordance with the invention, I provide a plurality of relays-in this case two relays 3 and Ill-that operate in conjunction with a photo-electric cell II and an amplifying tube I2 for automatically opening the energizing circuit of filaments 3 and closing an energizing circuit through filaments 4.

As mentioned above, the photo-electric cell II will be mounted upon the radiator or other convenient part of the automobile, where it will be subject to the headlight beams of approaching cars, and the rest of the apparatus may be conveniently housed behind the dashboard or under the hood of the car. The relay I0 is delicately sensitive to minute electric currents, whereas relay 9a much stronger relay-operates on stronger current.

The armature 9c of relay 9 is included in series in line 6; normally the armature stands in the position illustrated, closing through a contact 9a the circuit to the positive terminals of filaments The armature IUc of relay I0 is connected through a wire I3, a protective resistor I4, the

- actuating coil 9b of relay 9, and wires I5 and I6,

Such closing l closes circuit I3, I4, 9b, I5, I6, 2, I1; the actuating coil 9b of relay 9 is energized; thereupon the armature 9c swings from contact 9a into engagement with a contact 9d; the energizing circuit of filaments 3 is interrupted, and substantially simultaneously therewith a circuit through contact 9d, leads 6a. and lamp filaments 4 is closed. Thus, when the light beams of an approaching car impinge upon the photo-electric cell II, the light beams of lamps I, I are dimmed or deflected, and remain so, so long as the cell II is illuminated by the beams of the approaching car.l As the approaching car reaches and passes the car equipped with my apparatus, the'illumination of the cell II is abruptly terminated; the armature of relay I0 returns to open position; the actuating coil 9b of relay 9 is deenergized; and the relay armature 9c returns to its illustrated position, whereby the energizing circuit through filaments 4 is automatically interrupted and immediately closed through laments 3.. In such manner the headlights of a car may be automatically dimmed or deflected.

The use of a plurality of relays, or other electric make-and-break devices, operating on currents of unequal intensity, is important to successful operation of automatic headlight-controlling apparatus. Additionally, it is practically essential to convert the constant D. C. current of the battery 2 to a pulsating current, and it is essential to amplify the voltage of such pulsating current. In the following specification I shall describe means to these ends.

In the circuit between the battery 2 and photoelectric apparatus II, I2, I include a vibrator I8 and a rectifier-voltage-increasing tube I9. These devices are severally known in the electrical eld, and a consideration of the wiring diagram in Fig. I will afford a full understanding to those skilled in the art. Specifically, the vibrator I8 includes an actuating coil Ib, one of whose terminals is connected, by wire 20 including a radio frequency impedance (a filter choke-coil 2|), to the positive terminal of battery 2. The other terminal of the actuating coil |8b is connected, by a wire 22, including a protective resistor 23, to thewire I6 leading to the negative pole of the battery. The vibrator I8 includes an armature or reed I8c adapted to osciilate between two contacts |8a and Id. Contact I8d is by a wire 24 connected to the usual input plate |9a of the rectifier tube I9, and a wire 26, including a by-pass condenser 21 `(a radio frequency filter) in series, is connected across wires 24 and I8. The input cathode I9f of the rectier tube is connected to input plate |9a by means of lines 40, 26, and 24. The contact |8a of the vibrator is electrically connected to the terminal of actuating coil |8b from which wire 22 extends, while the armature I8c is by a jumper wire 28 connected to the other terminal of such coil, and a wire 29. including in series a by-pass condenser or radio frequency lter 30, establishes electric communication between the last-mentioned terminal of coil I8b and the wire I6.

In known way the armature I8c vibrates continuously when the switch 5 is closed and headlight filaments 3 are energized. The vibrating armature alternately engages the contacts I8a and Id, and causes a pulsating current to flow (through Wire 24) to the-input plate I9a and (through lines 24, 26, 40) to the input cathode I9f of tube` I9. In this case theA armature viof armature Ille with contact IIIa brates at the rate of approximately 120 cycles per second. Thus, a pulsating current is provided for the operation of the photo-electric lcell II and amplifier tube I2.

The rectifler tube I9 is so arranged in the circuit as to increase the effective voltage of such current. More specifically. the usual laments |917 and |9c of the rectifier tube I9 and the lamentl |2b of amplifier tube I2 are connected in parallel across the terminals of battery 2; that is, an electric line 25 runs from the wire 20, as

shown, to the positive terminals of the filaments,

while the negative terminals of the filaments are connected to wire I6, it being noted that the negative terminal of filament I2b is connected to wire I6, by means of a lead Ilia and wire I5. The anode I-Ia of the photo-electric cell II is, by lines 3| and 32, connected to the usual output cathode |9d, lying between input plate I9a and filament |9b of the rectier tube I9, and the cathode IIb of the photo-electric cell is by a lead 33 connected to the usual first-stage control grid I2a of the amplifier tube I2. The usual output plate |9e of the rectifier tube I9 is by a conductor 34 connected to a wire 35 that runs from the triode plate or anode |2c'of ampliiier tube I2 to a line 35a, and the linel 35a is connected to the output cathode I9d of tube I9, by means of conductor 32. A s already mentioned, the input cathode I9f of tube I9 is connected tothe source I8 of the pulsating current, by means of lines 40, 26, and 24. The .line 34 includes two resistors or impedances TI and r2; wire 35 includes two resistors or impedances r3 and r4, and it will be noted that the connection of line 34 to wire 35 is made between the resistors r3 and 14. The resistors TI, r2, and r4 form what is known in the art as a bias-network, which is effective to establish the proper voltages across the various elements of the amplifier tube I2, while the resistor r3 comprises a voltage-limiting resistor. The usual cathode I2d of the amplifier tube is by a lead 36 connected, in common with the suppressor grid I2f of the tube, to the conductor 34, the connection being made between the resistors-rl and r2. A limiting resistor or impedance R. for the first-stage control grid I2a of tube I2 is shunted from lead 33 to line 34, at a point between reresistor rI and the output plate I9e of the rectifier tube I9; the second-stage control grid I2e of tube I2 is connected to wire 35, at a point between the limiting resistor r3 and the triode plate or anode I2c, that is to say, the second-stage control grid I2c is connected in parallel with the triode plate I2c; the screen grid I2h is by a lead 31 and lines 35a and 32 connected to theoutput cathode I9d of the rectifier tube I9; .and the usual pentode plate or anode |2111I of the amplifier tube I2 is by a lead 38 connected, through the actuating coil IIlb of relay I0 and lines 35a and 32, to said-output cathode Ild f the rectier tube I9. The actuating coil Ib provides an impedance (or resistance) in circuit 38, 35a and 3| between the anode ofthe photo-electric cell and the output anode I2m of the amplifier tube I2. A pair of filter condensers c, c is connected in series across lines 34 and 35a, as shown, and from between these condensers a lead 39 extends into electrical union with the wire I6, leading to the negative pole of the battery 2. The condensers c, c and 21 provide a filter network between the vibrator I8 vwith its amplifier I9 and the photo-electric cell/ II with its amplifier I2.

the photo-electric apparatus, and as, those skilled in the art will readily perceive a pulsating current of augmented potential is supplied to the plate and grid elements of the amplifier tube I2 and to the anode and cathode of the photo-electric cell II, with the consequence and effect that, when the cell Il is illuminated by the headlight-beam of an automobile. a relay-operating current flows through the actuating coil Ib of relay ID, and continues to flow so long as such light beam plays upon the cell. Accordingly, the relay armature Ic closes, the relay 9 is energized, and the lamps I, I are dimmed or deflected in the manner described.

In modification of the apparatus described above, I illustrate in Fig. II that a step-up transformer I9 of known sort may be employed in place oi the rectiertube I9, to obtain the essential amplification of voltage, and with such transformer I employ a synchronous-rectifier vibrator I8 instead of the simple' vibrator I8 shown in Fig. I. The synchronous vibrator I8' is a known piece of apparatus, including two pairs of contacts a, b and c, d, and a single coni tact e; the contacts a and'b are severally connected, by leads 50 and 5I, respectively, to the opposite end terminals of the secondary coil |90 oi the transformer, and the contacts c and d are in like manner connected, by leads 52 and 53. to the end terminals of the primary coil ISI or" lthe transformer. A line 2IIJ, including a resister or `impedance r6, connects the one terminal of the vibrator actuating coil f with a line 20', leading through 'a choke-coil or radio frequency impedance or filter 2| to the positive terminal of the battery, and the contact e of the vibrator is connected to such line 2I0, at a point between the resistor r6 and the said terminal. of the coil f. 'I'he opposite terminal of coil f is by a line 54 connected to a wire I6', leading to the negative pole of the battery, and the armature or reed h of the vibrator is connected to said wire I6 by means of a lead 61. A wire 65, including a icy-pass condenser 56 in series, runs from the point of union of contact e with conductor 2I0 to the positive line 20', and a jumper 58, including in series a by-pass lter or radio frequency impedance 59, is shunted from the negative line I6' to said positive line 20'. Two condensers 60 and 6I forming a radio frequency filter are severally connected to the opposite terminals of the secondary coil |90 of the transformer, and such condensers are severally included in lines 62 and 63 leading through a wire |60 to the negative pole of battery 2. The center-tap |92 ofthe primary coil of the transformer is connected to the positive pole of the battery, by means of line 20. And the centertap |93 of the secondary coil of the transformer is by a Wire 64 connected to the input line 35a of the photo-electric cell II and amplifier tube I2, already described. Included in series in the line 64, 35a are a filter choke-coil 65 and a radio frequency choke-coil 66; a filter condenser 61 is connected across the input terminal of chokecoil 65 and the negative lead I 60; a filter condenser 66 in like manner is connected from negative lead |60 and to line 64, 35a, at a point between the series connected output terminal of choke-coil 65 and input terminal of choke-coil 66;A and a by-pass condenser 69 is connected across the output terminal of choke-coil 66 and said negative lead |66. And on the output side of the series connected choke-coils 65, 66 a jumper 10 connects the line 35a to the negative lead |60, through a voltage-limiting resistor RI'. This system of choke-coils and condensers forms a filter network between the output side of the transformer and the photo-electric cell and its amplifying tube I2.

In known manner the armature h of the synchronous vibrator I8 oscillates so long as switch is closed, and, in cooperation with the transformer I9' and battery 2', the vibrator supplies a pulsating current to the current input line 35a of the photo-electric equipment II, I2. The transformer serves to amplify thevoltage of the pulsating current to a value of several times the normal voltage of the battery 2', and, indeed, to a higher value than the rectifier tube I9 of Fig. I amplifles thevoltage of battery 2.

The electric hook-up of the photo-electric equipment II, I2, relays 9 and I6, and lamp filaments 3, 4 is substantially identical with that described in Fig. I, and a further consideration will not be required by persons skilled in the art, although the following qualifications may be mentioned: (First) between the anode IIa of the photo-electric cell and the positive feed line 35a, a voltage limiting resistor or impedance R2 is included; (second) in lead 31. from the screen grid I2h of the amplifier tube to said line 35a, a voltage-limiting resistor impedance 1'5 is included: (third) the negative lead I5a of the filament I2b of the amplifier tube I2, together with the line 34 leading from the elements I2c, |211,v

I2e and I 2f of the amplifier tube,'is connected, by wires I5 and |60, to the negative pole of the battery; and (fourth) the positive terminal of the filament I2b is connected to the -positive pole of the battery, by means of conductor 25, and in this case the lead I1 of the contact Illa of normal open relay I0 is connected to such positive conductor 25. Thus, it will be perceived that the synchronous-rectifier vibrator I8' and the step-up transformer I3 are organized with the photo-electric apparatus I I, I2, to effect in the manner already described the automatic dimming or deflecting of the light beams generated by the automobile headlight lamps I, I.

In order to eliminate any tendency for the amplifier tube I2 to operate sluggishly or lock" under the relatively high potential provided by the apparatus shown in Fig. II, a by-condenser 'II is connected between wire 34 and ground, and in like manner by-pass condensers 12 and 13 are severally connected between wires 35 and 31 and ground.

While I have said that the filaments 3 of the lamps I, I generate light of greater intensity than filaments 4, it is to be understood that the filaments may be of such structure as to generate light of equal intensity. In such case the effect sought by my invention is obtained solely by defiecting the light beams. More particularly,

each of lamps I, I may be so positioned in a headlight that its filament 3 lies substantially at the focus of the headlight reflector, with filament 4 lying above such focus. Accordingly the light beam generated when filament 3 is energized will be projected a relatively great distance in front of the car, while the beam projected when filament 4 is energized will be deflected downward. Of course, the filaments 3 and 4 may be embodied in vindividual lamps, so that each headlight will include two lamps, one lamp including a filament 3 and the other a filament 4.

In the two embodiments of the invention described, it will be understood that I convert D. C. current to pulsating current, and provide double the secondary ampliiier-as a single triode-pentode tube I2, but it is to be understood that two triode tubes, or two pentode tubes, or a triode tube and a pentode tube may be used in place of the single tube I2. I also contemplate that the two relays 9 and I0 may be embodied in a single unit capable of the double operation described. These modifications and others will present themselves to the engineer, without departing from the essence of the invention defined in the appended claims.

Notice is hereby given of an application for Letters Patent, Serial No. 132,966, iiled by me on the 25th day of March, 1937, covering an improved photo-electric cell for use in the practice of the above-described invention.

I claim as my invention:

. '1. In apparatus including in conventional assembly a source of D. C. energy, an electric lamp,

-a circuit connecting said lamp with said source, a

circuit-controlling device for said circuit, and light-sensitive means for operating said device; the herein described improvements in which said means include a photo-electric circuit connected to said source, primary and secondary electric amplifiers included in said photo-electric circuit, a current converter arranged electrically between said source and said primary amplifier, and a photo-electric cell arranged electrically between said primary and secondary ampliers.

2. In apparatus including in conventional assembly a source of D. C. energy, an electric lamp, a circuit connecting said lamp with said source, a circuit-controlling device for said circuit, and light-sensitive means for operating said device; the herein described improvements in which said means include a photo-electric circuit connected to said source and including a photo-electric cell and an amplifying tube, a current converter arranged electrically between said source and said cell, and a. fllter-network arranged electrically between said converter and said cell.

3. In apparatus including in conventional assembly a source of D. C.energy, an electric lamp,

, a circuit connecting said lamp with said'source,

a circuit-controlling device -for said circuit, and light-sensitive means for operating said device; the herein described improvements in which said means include a photo-electric circuit connected to vsaid source, primary and secondary electric ampliiiers included in said photo-electric circuit, a current converter arranged electricallyv Ybetween said source and said primary amplifier, and a' photo-electric cell arranged electrically between said primary and secondary ampliiiers, A

and a iilter network organized with said converter and primary amplifier and arranged electrically between such last-mentioned elements and said cell and secondary amplifier. w

4. In photo-electric apparatus for operating a circuit-controlling device, said apparatus including a source of D. C. current, a `photo-electric circuit connected to such source, and a photoelectricv cell and an amplifying tube included in such circuit, the herein described refinement in such apparatus which includes a current converter arranged electrically between said source and said cell, and a lter network arranged electrically between such converter and said tube.

5. In photo-electric apparatus for operating a circuit-controlling device, said apparatus including a source of D. C. current, a photo-electric circuit connected to such source, and primary and secondary electric amplifiers included in said photo-electric circuit, the herein described refinement that comprises a current converter arranged electrically between said source and said primary amplier, and a photo-electric cell arranged electrically between said primary and secondary amplifiers.

6. In apparatus including'in conventional assembly a source of D. C. energy, an electric lamp, a circuit connecting said lamp with said source, a circuit-controlling device for said circuit,y and light-sensitive means for operating said device;

the herein described improvements in said meansl that comprise a photo-electric circuit connected to said source; a current converter, primary and secondary amplifiers, and a photo-electric cell included in said photo-electric circuit; said cell including an anode and a cathode, said secondary amplifier comprising a tube including a control grid and an output anode, and van impedance arranged electrically between the anode of said cell and the output anode of said tube.

7. In apparatus including in conventional assembly a source of D. C. energy, an electric lamp, a circuit connecting said lamp with said source, a circuit-controlling device for said circuit, and light-sensitive means for operating said device; the herein described improvements in said means that comprise a photo-electric circuit connected to said source; a current converter, primary and secondary ampliers, and a photo-electric cell included in said photo-electric circuit; said cell including an anode and a cathode, said secondary amplifier comprising a tube including a control grid and an output anode, and an impedance arranged electrically between the anode of said cell and the output anode of said tube, and a filter network in said circuit between said amplifying tube and said converter.-

8. In apparatus including in conventional assembly a source of D. C. energy, an electric lamp, a circuit connecting said lamp with said source, a circuit-controlling device for said circuit, and light-sensitive means for operating said device, the herein described improvements in said means that comprise a relay and a photoelectric circuit for energizing said relay, said photo-electric circuit including a current converter, a photo-electric cell and primary and secondary ampliers, the actuating coil of said relay comprising animpedance between said cell and the output side of said secondary amplifier.

9. In apparatus including in conventional assembly a source of D. C. energy, an electric lamp, a circuit connecting said lamp with said source, a circuit-controlling device for said circuit, and light-sensitive means for operating said device, the herein described improvements in said means that comprise a relay and a photo-electric circuit for' energizing said relay, said photo-electric circuit including a current converter, a photoelectric cell and'primary and secondary amplifiers, the actuating coil of said relay comprising an impedance between said cell and the output side of said secondary amplifier, and a illter network connected electrically between said converter and said secondary amplier.

10. In photo-electric apparatus for operating a circuit-controlling device, said apparatus including in conventional assembly a relay for operating said device and a photo-electric circuit for operating said relay; the herein described improvements in said photo-electric circuit that comprise a source of D. C. current, a current converter, a. photo-electric cell including an anode and cathode, an amplifying tube including input and output elements, with the actuating coil of said relay connected between the anode element of said cell and the output element of said tube to provide an impedance between such elements.

11. In photo-electric apparatus for operating a circuit-controlling device, said apparatus including in conventional assembly a. relay for operating said device and a photo-electric circuit for operating said relay; the herein described improvements in said photo-electric circuit that comprise a source of D. C. current, primary and secondary amplifiers, a converter between'said source and said primary amplifier, a photo-electric cell between said ampliers, said cell including an anode and a cathode, said secondary amplifier comprising a tube including input and output elements, and an impedance connected between the anode of said cell and the output element of said tube.

12. The structure of the next-preceding claim, in which the actuating coil of said relay comprises said impedance.

HENRY A. BERG, JR. 

